How to reverse animate?
You can flip the animation around by actually inverting your animation data in your animation editor.


Go to your dope sheet editor.
Set the current frame to the beginning of the animation (probably frame one)
Select the frames you want to reverse. Press S and type -1
Move the inverted animation back to where it is supposed to be positioned (using G)
Play back the animation!


When you're scaling the frames by negative one, you are really just reversing the animation. Similar to turning a shirt inside-out.